In recent years, research is in progress of a light-emission element having a light-emission layer that contains light-emission material such as organic light-emission material and inorganic light-emission material. One example of such a light-emission element is an organic electroluminescence element (hereinafter referred to as an “organic EL element”). An organic EL element is an example of a current-driven light-emission element. An organic EL element makes use of an electroluminescence phenomenon of organic light-emission material. For example, a typical organic EL element includes a thin film transistor (TFT) substrate, an anode made of a metal such as Al, a light-emission layer made of an organic light-emission material, and a cathode that is made of a transparent material such as Indium Tin Oxide (ITO). In the organic EL element, the TFT substrate, the anode, the light-emission layer, and the cathode are layered in the stated order. Further, an organic EL element may include, in addition to the above, such layers as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and a sealing layer, as necessary.
A light-emission element such as an organic EL element is widely used in a light-emission device or the like. One example of such a light-emission device is an organic EL display panel having one or more organic EL elements disposed above a substrate. In addition, to realize display in color, a light-emission device, such as an organic EL display panel, including a plurality of light-emission units each of a different light-emission color is in practical use.
Here, one technical problem related to a conventional light-emission device is the problem that a light-emission element included therein undergoes degradation due to heat generated by a light-emission layer included in the light-emission element during light emission. As countermeasures against this problem, proposals have been made of light-emission devices capable of discharging heat generated by a light-emission layer included therein to the outside (Patent Literatures 1 and 2). One of such light-emission devices discharges heat generated by the light-emission layer to the outside via a heat discharge member that is disposed facing the substrate of the light-emission element and that is composed of a heat discharge sheet and a metal plate. Another one of such light-emission devices discharges heat generated by the light-emission layer to the outside via a black matrix portion that is disposed surrounding an entirety of the light-emission unit and that is composed of material having high heat conductivity.